One possible X factor arising today is the sideline maneuvering of Sen. Ben “Gang of 14” Nelson. He’s staying true to form by trying to build a bipartisan coalition of senators to support major changes to the House bill.Nelson is talking about increased infrastructure spending, which sounds good, but also cutting health and education aid that leaders in both chambers hold dear. Sen. Susan Collins (R-ME) is reportedly joining in this effort, though it’s unclear whether these are the same talks that are also attracting John McCain.

To an extent, these crafty moves on the sideline are part of the Senate culture. It happened on judges with the Gang of 14, it happened on energy with the “Gang of 10,” and it even happened during the 2007 debate over cutting Iraq war funding — which ended with “benchmarks” for progress that Nelson helped write. That these bipartisan meetings are occurring means only that it’s a normal workday.

But if Harry Reid called the stimulus up for a vote next week, would he have the votes? He might not have Sen. Kent Conrad (D-ND), who said on Fox today …

Look, I’d have a very hard time voting for what came over from the House. While there is much in it that’s laudable and good, there are other areas of the package that I think, really, are very questionable in terms of whether they’d stimulate the economy.

The Senate stimulus differs from the House version in some marked ways, including a fix for the alternative minimum tax and more generous business tax cuts. But the Republican who led the charge to add the AMT, Chuck Grassley (R-IA), has blasted the process behind drafting the bill and looks likely to oppose it.

Sen. Olympia Snowe (R-ME), who backed the stimulus’ tax cut portion last week, looks gettable. If Reid loses one or two Democrats, however, he’d need to make up that deficit on the GOP side — Dems now hold a 58-41 majority, until the Minnesota race is resolved.